A/C System - Apparent Erratic Operation

Bulletin No. T 87-3
File in Group 1
Number 29
Corp. Ref. No. 611101
Date Sept. '86

SUBJECT: UNWANTED BLOWER OPERATION OR IMPROPER AIR DELIVERY FROM ELECTRONIC CLIMATE CONTROL (ECC)

MODELS AFFECTED: 1986 ELDORADO AND SEVILLE

1986 Eldorados and Sevilles are equipped with a BCM controlled Electronic Climate Control (ECC) system that will, under certain conditions, operate the blower with the ECC in the "OFF" position or direct air delivery to the A/C vents with the ECC in front defrost mode.

The ECC system is programmed with a mode called Instrument Panel Cluster (IPC) cooling. The purpose of this mode is to prevent the IPC from overheating under high ambient temperature conditions. The ECC system will enter this mode if all of the following conditions are met:

- The ignition is in the run position.
- The in-car temperature is greater than 93~F or the sun load temperature is greater than 105~F.
- The engine is not running or the HVAC is in the off setting or the HVAC is in the front defrost setting.

When the ECC system enters the IPC cooling mode, the blower will operate at a medium speed and the ECC will deliver air through the A/C vents. This mode will not affect compressor operation.

This condition is normal. No attempt should be made to repair a vehicle with this condition.